Human Papillomavirus, Helicobacter, And Feline Fluke: Infections Implicated In Cancer

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Human Papillomavirus, Helicobacter, And Feline Fluke: Infections Implicated In Cancer
Human Papillomavirus, Helicobacter, And Feline Fluke: Infections Implicated In Cancer

Video: Human Papillomavirus, Helicobacter, And Feline Fluke: Infections Implicated In Cancer

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Human papillomavirus, Helicobacter, and feline fluke: infections implicated in cancer

Chronic infections account for about 16% of all cases of cancer. There are several known pathogens of infections that provoke cancer. Timely vaccination protects against some, and compliance with elementary sanitary rules protects against others. Natalya Isaeva, leading expert of the Center for Molecular Diagnostics of the Central Research Institute of Epidemiology, talks about microorganisms that can trigger cancer.

Human papillomavirus, Helicobacter, and feline fluke: infections implicated in cancer
Human papillomavirus, Helicobacter, and feline fluke: infections implicated in cancer

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Chronic infections account for about 16% of all cases of cancer. Several pathogens of infections that provoke cancer are known to modern medicine. Timely vaccination protects against some, and compliance with elementary sanitary rules protects against others. Natalya Isaeva, a leading expert of the CMD Center for Molecular Diagnostics of the Central Research Institute of Epidemiology of Rospotrebnadzor, a member of the American Association for the Study of Cancer (AACR) and the European Society of Medical Oncology (ESMO) Natalya Isaeva, talks about microorganisms that can become a triggering mechanism for oncology.

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Human papillomavirus (HPV)

Why is it dangerous?

HPV is a proven cause of cervical cancer by Nobel laureate Harald zur Hausen. This is the most common cancer in women 30-40 years old, and is often detected during pregnancy. It is also reliably known about the relationship of HPV with the development of tumors of other localizations (including in men). As a rule, the peak of infection occurs between the ages of 25 and in the interval from 35 to 45 years. Precancerous conditions most often develop in women aged 25-30, and by the age of 40-45, missed “precancerous” often turns into cancer, and there is a tendency for this age to decrease.

To date, more than 130 types of HPV are known. Among them there are those that cause papillomas and warts, which in itself is not associated with the risk of developing malignant neoplasms. But there are some that have carcinogenic potential. The most dangerous in terms of the ability to transform a normal cell into a cancerous one are 16 and 18 types.

Human papillomavirus infection is the most common sexually transmitted infection in the world. However, only its long-term presence in the focus can lead to changes at the cellular level (dysplastic processes). More than 80% of those infected with HPV heal spontaneously within 1–2 years. There is currently no cure for the human papillomavirus.

What to do?

To find out about the state of the cervix at the current moment, it is necessary to periodically perform a cytological examination. The detection of a high carcinogenic risk virus (HPV HRS) in the absence of changes in the cytological preparation, as well as the detection of insignificant cytological changes in the absence of HPV HRS, is a signal for active observation. If more serious transformations of the cervical epithelium are detected, the only effective method of treatment is to remove the area affected by the virus.

To prevent infection with the virus, you should get vaccinated. The vaccine is recommended for all girls / women aged 9 to 45 years, and the vaccine against four genotypes (16, 18, 6,11) is also approved for use in the male population of the Russian Federation aged 9 to 26 years.

Hepatitis B and C viruses

Why are they dangerous?

These viruses are responsible for acute and chronic inflammatory lesions of the liver (hepatitis). Without timely diagnosis and treatment, the acute process becomes chronic. Chronic liver damage can lead to cirrhosis and even liver cancer. And due to the asymptomatic course of chronic hepatitis, some patients seek help when the pathological process has already reached these stages.

Contrary to stereotypes, viral hepatitis B and C is not at all a disease of people at risk. These viruses are not only transmitted sexually, but also through contact with the blood of an infected person. This means that the potential risk is represented by other people's personal hygiene products and everyday manipulations, in which non-sterile instruments can be used: manicure, shaving, cosmetic procedures, visits to the dentist.

What to do?

Today, the national immunization schedule includes vaccination against hepatitis B, which is given in the first 24 hours of a child's life. As for hepatitis C, the virus is highly variable and there is no vaccine for it, but the disease itself is potentially completely curable. In order not to miss the disease, you should periodically do a screening test to identify the antigen of the hepatitis B virus (HBsAg) and antibodies to the hepatitis C virus (anti-HCV) in the blood.

Epstein-Barr virus (EBV)

Why is it dangerous?

This is a pathogen from the herpesvirus group, which in most cases leads to the development of infectious mononucleosis. By its symptoms, this disease resembles a common cold: high fever, runny nose, sore throat. Only inflammation of the lymph nodes is atypical. There is also evidence of a link between this virus and chronic fatigue syndrome. Many people have no symptoms at all. Unlike other herpes viruses, EBV does not cause cell death, but activates cell division, that is, it can trigger malignant proliferative diseases of blood cells (lymphogranulomatosis, Burkitt's disease). There are also indications of the link between EBV and nasopharyngeal cancer and other diseases. The presence of membrane proteins in this virus allows it to “escape” from immunological control, thereby helping the infected cell to stay “alive”.

What to do?

An effective vaccine against the Epstein-Barr virus does not exist, in particular, due to the difference in protein composition at different phases of the virus life cycle.

Since the virus is transmitted mainly by airborne droplets, it is worth avoiding contact with an infected patient in the active phase, not visiting, if possible, places of large concentrations of people. When symptoms occur, it is very important to identify the virus that caused the illness. A test for antibodies to the capsid (VCA) and nuclear (EBNA) antigens of the virus will allow timely treatment and relief of symptoms.

Helicobacter pylori

Why is it dangerous?

75% of stomach cancer cases are associated with Helicobacter pylori, discovered in 1982 by Australian scientists Barry Marshall and Robin Warren. Later, for this discovery, the Nobel Prize was awarded, and the bacterium itself was recognized as a class I carcinogen, that is, very dangerous in relation to the development of cancer.

It is a spiral-shaped bacterium that lives in the lower part of the stomach that passes into the duodenum. The transmission occurs by contact and household, through hygiene items, dishes and airborne droplets. The presence of this infection can be indicated by characteristic gastric symptoms - pain, discomfort, heartburn. But sometimes there may be no symptoms at all. The defeat of the mucous membrane gradually from the moment of infection can lead to the development of stomach cancer.

What to do?

Fortunately, Helicobacter is fairly easy to detect and eliminate with a course of antibiotics. The most informative laboratory test, which in some cases avoids gastroscopy, is the urease breath test, which is based on the ability of Helicobacter pylori to produce the urease enzyme in order to survive in the aggressive acidic environment of the stomach. By the urease activity, one can judge the activity of the vital processes of a potentially oncogenic pathogen. Alternatively, feces can be tested to detect bacterial antigens.

Mycobacterium tuberculosis

Why is it dangerous?

Mycobacterium tuberculosis (Koch's bacillus), long known to mankind, is an intracellular pathogen that is very resistant in the environment, transmitted by airborne droplets and causes tuberculosis. Tuberculosis is considered a socially dangerous disease and has long gone beyond the disadvantaged population. Although this bacterium is not directly related to cancer, there is evidence that among patients with tuberculosis, the risk of lung cancer increases 11 times.

What to do?

The disease develops only in 5-10% of those infected. A latent infection, in which there are no clinical symptoms, in an unfavorable situation can turn into an active form of tuberculosis. That is why children are regularly tested for mycobacterium. Today, in addition to intradermal tests, there is a high-precision laboratory method - the quantiferon test, which is capable of detecting both active and latent forms of infection. This is a blood test that determines the patient's level of specific interferon gamma (IFN-γ), which is produced when a human blood lymphocyte comes into contact with a bacterial antigen. Those uninfected or vaccinated with BCG will have a negative result.

Cat fluke

Why is it dangerous?

Helminthiasis, the causative agent of which in Russia is Opisthorchis felineus (feline fluke), can lead to liver cancer. These are parasitic flatworms that live in some types of fish (roach, roach, chebak, ide, dace, rudd, bream, crucian carp, tench). The source of infection is domestic and wild animals that feed on fish containing helminth larvae. And also a person who eats raw or insufficiently cooked fish. As a result, opisthorchiasis develops, often asymptomatic, in which the ducts of the liver, gallbladder and pancreas are damaged.

What to do?

The diagnosis of "opisthorchiasis" is made on the basis of clinical data and the results of laboratory blood tests, as well as analysis of feces for helminth eggs and protozoan cysts. To avoid infection, it is necessary to refuse meals from raw or slightly salted fish, especially in areas endemic for opisthorchiasis. And to observe elementary sanitary rules - do not use the cutting board on which raw fish was cut for other products.

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